Candido Lopez, Desembarco del Ejército Argentino frente a las trincheras de Curuzú, el día 12 de Septiembre de 1866
Between April 1865 and April 1867, several thousand soldiers began a slow journey over the hills and through the forests of southern Brazil. The men, part of the Mato Grosso Expeditionary Force, had been ordered by Brazil's Emperor to march west to fight the Paraguayan army on behalf of their nation and allies, Argentina and Uruguay. But they had to get there first, and 3,000 kilometers of rough terrain separated them from their enemies. The soldiers traveled by river when possible, or took trails traversed by the indigenous, traders, and adventurers of Brazil’s remote western frontier. The journey, taking two years, was greatly slowed by what the soldiers brought: heavy artillery, ammunition, supplies, and a herd of cattle over paths that were often too narrow, too muddy, or frustratingly obstructed by steep hills, wide rivers and malarial swamps. They stopped more than they moved. In such pauses, soldiers surely talked about the much easier and faster route to their destination. Some, in fact, may have already traveled to Mato Grosso by sail or steam down the Atlantic coast, into the Rio de la Plata and up the Paraná or Paraguay Rivers; a two month journey. The ship route, however, had been blockaded by Paraguayan forces by the time the expedition set out for Mato Grosso. Furthermore, officers spoke of the need to repel a malevolent invasion and to compromise their enemy’s defenses by creating a new northern front.
When the column arrived after their arduous journey, they were weak and ill-prepared. Several early battles turned against them and they retreated into Brazilian territory, pursued by Paraguayan cavalry regiments. Soon, however, they had to contend with a new and even more frightful enemy that took no visible form and used no bullets to fell the fiercest warrior. On May 18th, pained cries were heard from three soldiers struck by cholera. Two days later the disease had spread so rapidly that the column’s carts and wagons filled with deathly ill soldiers. The epidemic prevented the Brazilians from finding a suitable defensive position against Paraguayan forces, whose continued attacks drove the column through jungle and brush, deeper into their heartland. To prevent total loss, officers ordered the sick abandoned and once tied a large sign from a tree branch asking mercy for the infirm. Of the original 2,700 soldiers of the Mato Grosso Expeditionary Force, only 700 made it to safety at the Aquiduana River. More soldiers had died from disease than from enemy bullet or blade; in addition to the havoc wrought by cholera, there were a host of other dangerous afflictions, including other gastro-intestinal illnesses, smallpox, and malaria.
This tragic episode, called the Retirada da Luguna (Retreat from the Lagoon), became a popularly recounted story of bravery against all odds to Brazilians. Although Brazil and its allies won the war against Paraguay in 1870, victory came at an awful cost, leading the Imperial government to lose legitimacy and fostering foundational support for a republican movement that eventually toppled the monarchy. The loss for Paraguay was even more severe: The government was overthrown, the army destroyed, and between one third and one-half of the nation’s total population was killed, including most working age males. Beyond a symbol of tragedy and heroism, the Retirada also demonstrates how the epidemiological environment of a wide region of the southern interior of South America was disrupted by the importation of epidemic diseases. Like most other wars of the nineteenth century, more soldiers were killed from illness than enemy combat in the Paraguayan War. And as in the Crimean (1853-56) and Austro-Prussian (1866) Wars, cholera may have been the top killer. Historians know little about this disease and the role it played despite the damages it wrought. Important yet unanswered questions include: Who or what carried the vibrio cholerae into the theater of war? How long did it persist? What was morbidity and mortality of the outbreak or outbreaks? Did cholera affect one army more than the other, perhaps quickening or delaying the Allied victory? What was the effect of imported diseases on the wider region? While more comprehensive answers will come with the publication of Brazil’s Era of Epidemics, some clues to help understand the context of the war and cholera’s impact and be found by clicking here.
This post was co-authored with Agnes Conrad.
 Alfredo d'Escragnolle Taunay Tauny and Afonso de E. Taunay, A retirada da Laguna; episodo da guerra do Paraguay (São Paulo: Comp. melhoramentos de S. Paulo (Weiszflog irmãos Incorporada), 1935).
 In May and June, the final months of the operation, 30 soldiers and officers were killed in combat. Ten times as many were killed by cholera. Jourdan, E. C., Historia das campanhas do Uruguay, Matto-Grosso e Paraguay (Rio de Janeiro: Imprensa Nacional, 1893) 103.